Telephonic apparatus.



H. C. EGERTON.

TELEPHONIC APPARATUS. APPLICATION man :AN.22,1914.

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H. C. EGERTON.

TELEPHONIC APPARATUS.

APPLICATION FILED IAN.22, I914.

1,140,366. v Patented lIIaJy2/5,1915.

2 SHEETS-SHEET Z.

U IWIIIIIIIIIIII" E IMM" -f fa- VV/'fnessess UNITED sTaTEs PATENT. oEEIcE.

' HENRY CLIFFORD EGERTON, OF PASSAIC, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY", OIE' NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

TELEPHONIC APPARATUS.

To all whom it may concern:

Be it known that I, HENRY CLIFFORD EGERTON, a citizen of the United States, residing at Passaic, in the county Lof Passaic and State of New Jersey, have invented a certain new and useful Improvement in Telephonie pparatus, of which the following is a full, clear, concise, and exact 'description.

, nent magnet.

This invention relates to telephone receivers and more particularly to a telephone receiver for amplifying the received voice currents. n The object of this invention is to provide a new and improved device of this character of few and simple parts, efficient in operation and Aeasily maintained.

In accordance with this invention there is combined in a single structure two independentl'y operable receiver structures having certain of their parts in common. Both structures are o erated with a single permaossibilities of cross talk or interfereuce between the two receivers is eliminated -by reason of a differential magnetic circuit. The device is rendered compact in form and easily assembled by the details of construction and means provided for the mounting of the parts.

In the Adrawings illustrating this invention,*Figure 1 is a plan view of the device with the cover removed and parts in section;

Fig. 2 is a sectional view taken upon line 2-2 of Fig. 1; Fig. 3 is a perspective of the magnet system of the device; Fig. 4 is a detail sectional view taken upon line 4,--4'of Fig. l; and Fig. 5 is a diagram of the magnetic circuit of the device g As shown in the drawings', there is provided a frame member comprising a generally rectangular portion f5, having an extension 6 thereon opening into the rectangular portion 5 and having formed therein seats 7 for diaphragme 8, 8. The rectangu* lar portion 5 is divided into two compartments 9,` 9 by means of a partition wall l0 located centrally of said rectangular portion. 'Located ineach of these compartments 9, 9 is an electromagnet comprising two coils 12, 12, and one arm 13 of a horseshoe magnet 14, the main portion of which is located in the frame extension 6. The coils 12, 12 of each electromagnet are supported upon extensions 15, 15, of a' magnetic Specification of Letters Patent.

being provided with an adjustable core 20.

Located between each pair of coils 12, 12 is a supporting block 21 vfrom which is supported a lever arm l22. Each lever arm has knife edge extensions 23, 23 engaging notches inthe supporting block 21 and is maintained in position by means of a sus- Patentea May 25, 1915;' Application tiled January 22, 1914. Serial No. 813,662.

pending wire 24 secured to said lblock 21 and passing through an opening 25 in a projection 26 carried by said lever arm. Secured to said lever arm 22 at equal distances upon each side of the extensions 23,23 are plunger members 28, 28 'of magnetic material which project into the solenoids 12, 12 and are attracted and repelled by the magnetism set up in said coils by the energization thereof. The lever arm 22 extends into the -frame extension 6 and is secured to the diaphragm 8. Secured to the frame extension 6 is a supporting member 30 for a sound deflector, havingY two angularly disposed openings 31, 31, one opening directly above the central portion of a 'diaphragm 8 and the two openings verging into one near the outer end of the support to which a sound deflector or horn may be attached. Top and bottom cover plates 35 and 36 are secured to the frame by means of screws 37,

37. Wires may be led into terminals 38, 38 f within the casing through insulating bushings 39, 39 secured therein.

Referring now to Fig. 5 in which the magnet system is shown diagrammaticallm let/40 and 41 designate the line wires connecting with the electromagnets of one receiver and 42 and 43 the line wires connecting with the electromagnets of the other receiver. Assuming that a conversation vis being carried on over the line wires 40 and 41, this will cause an unbalance in the maga'f netic circuit of the solenoids associated withn these Aline wires, but not in that associate with the other line wires in spite of the fact that the permanent magnet 14;and the yoke 16 are common to the two'receivera This is l the electroinagnets which are not receiving equally between the cores and plungers of energizing current. "that there is a magnetic liux through the As illustrative, assume magnetic circuit including the polarized magnet 1l, the plungers 28, 28, the cores 20, 20 and the yoke 16 and its extensions 15, 15 of a strength say of sixteen units. This Will under ordinary lcircumstances divide the electromagnets so that the system will be in a state of equilibrium. If, however, there is talking current overpthe Wires 40 and 41, it will cause an imbalance in the magnetic circuit ofthe solenoids associated therewith, causing say twelveunits to iiow through the core and plunger of one sole# noid and only four units through the core and plunger of the other solenoid; thus causing the movement of the lever arm controlled thereby.l Due, however, to the fact that the return path for these lines of force is through theyoke16, which is common to thetWo eleetromagnets, they must all flow therethrough and will divide equally bei tween the cores and plungers of the other solenoids without aecting the lever arm controlled thereby. 'Ihis'structure permits of the independent operation of two receiverslwith a single.permanent'magnet Without interference or crosstalk between them. This not only reduces the cost oi? the equipment for installations of 4this type but sim pliies'the construction and makes easier thev maintenance of the apparatus.

1. Two independently operable telephone receivers haring' a connnon dillezntial mag notie ciicnit. "f,

2, 'Een indepemlentl-r operable telephone receiiers haring in common apermanent magnet and a magnetic return path.

fi. Two independentlyv operable telepl'ionic receivers having in rfnnrnon a permanent maget, a magnetic .return path and\a sound delector. 1l. ln a ltelel'ihonic device, a pair of diaphragms, independently operable electromagnetscontrolling the operation ot`\\said diaphragme, and means vliorn'iing a, dillrentrom'a gnets,

lar portion and tial magnetic circuit for said electromaglv 55Y nets.

5. In a'telephonic device, a pair of dinphragms, independently operable velectroy magnets controlling the operation of saidv diaphragms, and a magnetic circuit common to said independently operable electro-- magnets.

" 6. In a telephonie device, a pair of dlphragms, independently operable electro` magnets controlling the operation of said. diaphragms, a permanent magnet common to both said electromagnets, and a yoke common to both said electromagnets.

7. In a telephonie device, a pair of die` phragms, independently operable electro- 70 magnets controlling the operation `of saidy J diaphragms, a permanent magnet having one p ole.-associated with each of saidelecand a yoke of magnetic mate;` rial forming a common return magnetien4 path for both said electromagnets.

8. In a telephonie device, a pair of dia-vf phragms, an electromagnet operatively con# nected with each of said .diaphragms, i'. frame for said electromagnets", a partitionv dividing,4 said frame into compartments,l each inclosing an electromagnet, a peruu-J nent magnet having one pole in each of said compartments, and a yoke for said electromagnets secured to said partition. l86

9. .In a telephonic device, a pair ciglia-f' phragms, an electromagnet opera'tveljfcon nected with each of saiddjaplagms, porting frame comprising* a rectang'u'lu;- i. frame inembeif'li/aving an extension ther5, N saic-h'ktension opening into said""rectangl1 being provided with seats f tor said diaphragms, a partition dividingy said rectangular portion into two compari;- j ments in which are located said electromag- "9,1 nets, a permanent magnet having onel located in each otl said compartments ax i its main portion in said extension, and "5a., connecting yoke supporting said electromag-` nets secured to said partition. fill ln witness whereof, I hereunto subscribe my naine tliisZOth day of January `A.D., 1914. v

Witnesses:

ALICE HAZLEY, NANoA E. TU'rmLL. 

